While most people know that physical activity is healthy, it’s estimated that about 30% of people worldwide don’t get enough. Unless you have a physically demanding job, a dedicated fitness routine is likely your best bet for getting active. Unfortunately, many people feel that they don’t have enough time to exercise. If this sounds like you, maybe it’s time to try High Intensity Interval Training (HIIT). HIIT is a broad term for workouts that involve short periods of intense exercise alternated with recovery periods. One of the biggest advantages of HIIT is that you can get maximal health benefits in minimal time. In this article, you will know what HIIT is and the 9 benefits of High Intensity Interval Training (HIIT).
HIIT is any form of exercise that consists of a short burst of intense exercise that precedes a period of rest or low-intensity exercise. The period of intense exercise can vary from less than 45 seconds to a few minutes. People then rest or do gentle exercise for a similar time frame before repeating the sequence. An entire HIIT workout may be as short as 15–20 minutes, but it provides a wide range of benefits. Its short duration can make it a very practical and effective choice for people who find it difficult to commit to longer sessions. HIIT also requires no equipment or gym membership, so people can do it anywhere at a time that suits them.
You can burn calories quickly using High Intensity Interval Training (HIIT). One study compared the calories burned during 30 minutes each of HIIT, weight training, running and biking. The researchers found that HIIT burned 25–30% more calories than the other forms of exercise. In this study, a HIIT repetition consisted of 20 seconds of maximal effort, followed by 40 seconds of rest. This means that the participants were actually only exercising for 1/3 of the time that the running and biking groups were. Although each workout session was 30 minutes long in this study, it is common for HIIT workouts to be much shorter than traditional exercise sessions. This is because HIIT allows you to burn about the same amount of calories, but spend less time exercising.
Despite the benefits of exercise, not everyone is keen or able to commit to regular sessions. One of the most common barriers is a lack of time. High Intensity Interval Training (HIIT) is an efficient way to exercise, and it may, therefore, be a good choice for people who find it difficult to fit physical activity into their schedule. According to a 2014 study, a commitment of just 30 minutes three times a week could be beneficial.
The researchers found that each of these 30 minute sessions had to include just 10 minutes of intense exercise for the person to gain the following benefits:
Researchers saw these benefits after just a few weeks in both healthy participants and those with cardio and metabolic conditions.
Studies have shown that High Intensity Interval Training (HIIT) can help you lose fat. One review looked at 13 experiments and 424 overweight and obese adults. Interestingly, it found that both HIIT and traditional moderate-intensity exercise can reduce body fat and waist circumference. Additionally, one study found that people performing HIIT three times per week for 20 minutes per session lost 4.4 pounds, or 2 kgs, of body fat in 12 weeks — without any dietary changes. Perhaps more important was the 17% reduction in visceral fat, or the disease-promoting fat surrounding your internal organs. Several other studies also indicate that body fat can be reduced with HIIT, despite the relatively low time commitment. However, like other forms of exercise, HIIT may be most effective for fat loss in those who are overweight or obese.
In addition to helping with fat loss, High Intensity Interval Training (HIIT) could help increase muscle mass in certain individuals. However, the gain in muscle mass is primarily in the muscles being used the most, often the trunk and legs. Additionally, it’s important to note that increases in muscle mass are more likely to occur in individuals who were less active to begin with. Some research in active individuals has failed to show higher muscle mass after HIIT programs. Weight training continues to be the “gold standard” form of exercise to increase muscle mass, but high-intensity intervals could support a small amount of muscle growth.
High Intensity Interval Training (HIIT) may have important health benefits, as well. A large amount of research indicates that it can reduce heart rate and blood pressure in overweight and obese individuals, who often have high blood pressure. One study found that eight weeks of HIIT on a stationary bike decreased blood pressure as much as traditional continuous endurance training in adults with high blood pressure. In this study, the endurance training group exercised four days per week for 30 minutes per day, but the HIIT group only exercised three times per week for 20 minutes per day. Some researchers have found that HIIT may even reduce blood pressure more than the frequently recommended moderate-intensity exercise. However, it appears that high-intensity exercise does not typically change blood pressure in normal-weight individuals with normal blood pressure.
Oxygen consumption refers to your muscles’ ability to use oxygen. And, endurance training is typically used to improve your oxygen consumption. Traditionally, this consists of long sessions of continuous running or cycling at a steady rate. However, it appears that High Intensity Interval Training (HIIT) can produce the same benefits in a shorter amount of time. One study found that five weeks of HIIT workouts performed four days per week for 20 minutes each session improved oxygen consumption by 9%. This was almost identical to the improvement in oxygen consumption in the other group in the study, who cycled continuously for 40 minutes per day, four days per week.
Another study found that eight weeks of exercising on the stationary bike using traditional exercise or HIIT increased oxygen consumption by about 25%. Once again, the total time exercising was much different between groups: 120 minutes per week for the traditional exercise versus only 60 minutes per week of HIIT. Additional studies also demonstrate that HIIT can improve oxygen consumption.
Although all exercise may benefit mental health, High Intensity Interval Training (HIIT) training may be especially helpful. The authors of a 2019 review suggest that HIIT can provide a range of benefits for people with mental illnesses, including reducing the severity of depression. Although the review looked at 12 studies, the authors stated a need for further high-quality trials to support these findings.
A 2015 study looked at the effects of HIIT training on people with chronic schizophrenia. The research found that many people with psychiatric conditions had low motivation to exercise and felt that exercise was too time-consuming. Short HIIT workouts could help overcome difficulties with motivation and finding time to exercise. The study recorded the effects of an 8-week program of HIIT workouts in people from a psychiatric daycare unit. The program consisted of three workouts a week. Each of which was 15 minutes long with 5 minutes warming up and cooling down either side.
Of the 20 participants, 18 completed the program. The results showed the following mental and physical improvements:
One of the ways High Intensity Interval Training (HIIT) helps you burn calories actually comes after you are done exercising. Several studies have demonstrated HIIT’s impressive ability to increase your metabolic rate for hours after exercise. Some researchers have even found that HIIT increases your metabolism after exercise more so than jogging and weight training. In the same study, HIIT was also found to shift the body’s metabolism toward using fat for energy rather than carbs. Another study showed that just two minutes of HIIT in the form of sprints increased metabolism over 24 hours as much as 30 minutes of running.
Blood sugar can be reduced by High Intensity Interval Training (HIIT) programs lasting less than 12 weeks. A summary of 50 different studies found that not only does HIIT reduce blood sugar. But, it also improves insulin resistance more than traditional continuous exercise. Based on this information, it is possible that high-intensity exercise is particularly beneficial. Especially, for those at risk for type 2 diabetes. In fact, some experiments specifically in individuals with type 2 diabetes have demonstrated the effectiveness of HIIT for improving blood sugar. However, research in healthy individuals indicates that HIIT may be able to improve insulin resistance even more than traditional continuous exercise.